Synthesis and characterisation of Co(II), Ni(II), Cu(II) and Zn(II) complexes with a schiff base ligand derived from benzaldehyde and 4,4 diaminobiphenyl

The Schiff base ligand was prepared by condensation of 4,4 diaminobiphenyl (benzidine) with benzaldehyde in 1:2 molar ratio in an alcoholic medium. The transition metal(II) complexes were synthesized by the reaction of the metal(II) salts with the Schiff base ligand in 1:2 M ratio (M:L). The ligand and its metal(II) complexes were characterized using physical, elemental analysis, infrared(IR) and V/Vis spectroscopy. The compounds showed various shades of colours and all are air stable. The IR data revealed that the ligand acted as a bidentate ligand, coordinating to the metal ions through the N atoms of the azomethine group. Absorption bands in the UV region were assigned to π-π* or intra ligand transitions of the ligand. In the visible region, only broad bands were observed and are assigned to d-d transitions of the metal ions. Microanalysis for the ligand and the metal(II) complexes indicated that the compounds have a general formula: [ML₂].